As a kid, odds are that you used to play around with flipbooks from boxes of Cracker Jacks or in fast-food kids’ meals. These simple playthings turned static pictures into active motion – or at least they created the illusion that they did. Flipbooks represent a much larger category of optical illusions, pictures or processes that trick the mind into thinking it’s seeing something it’s not.

For the most part, optical illusions are novelties. As an adult, you might mess around with a flipbook for a minute or two, but it loses its charm not long after that. However, your brain processes a hundred million visual cues every day, so you might not even notice when you’re actually seeing something that’s not there – which is the exact way that glasses-free 3-D television and computer displays work to project multidimensional pictures without the need for any other accessories.

The early days of 3-D
High-definition displays may be the current king of the television marketplace, but 3-D TVs are quickly becoming the mark of the modern entertainment center. However, it’s no wonder why many consumers have resisted the idea of buying a TV that requires extra equipment just to watch your favorite shows, which is why techniques before glasses-free 3-D weren’t exactly as cutting-edge as the name would imply.

Pop culture and entertainment news site IGN explained that in the late 19th and 20th centuries, cinemas used to employ novel strategies to offer moviegoers the newest experiences the booming technological advancement of the time afforded them. Adventurous theater owners would broadcast two similar but slightly different images onto two separate screens and audiences would use a device called a “stereoscope,” a handheld viewing glass that combined the pictures.

Though the quality wasn’t anything to write home about, it proved popular as a way to enhance the movies of the Silent Era. IGN explained that this was a frequent trend with early 3-D technology – new methods proved technically successful, but not exactly marketable due to its poor quality and gimmicky eyewear accessories.

Eye on the prize
Like most technologies, 3-D couldn’t be held back forever. Around the start of the 21st century, electronics review site Tom’s Guide explained that engineers figured out how to make glasses-free 3-D a reality with a bit of digital trickery.

To explain how this method works, it helps to know just how your brain interprets the visual cues your eyes send it. Provided your eyes are shaped in such a way that they focus incoming light at the right point – directly on the retina – your brain receives two clear images of a single scene from each of your eyes. Using the slight differences in visual cues between the pictures, your brain combines them into a composite that contains something that neither two-dimensional picture had: depth.

The key then, Tom’s Guide explained, is figuring out how to send the brain two separate images from a single TV screen. Designers solved this riddle by installing a liquid crystal display layer that could be selectively changed onto the original display layer. Called a parallax barrier, this line of electronic cells can be activated to selectively block light signals to send independent images to the eyes of each viewer in the audience.

Dreams of3-D
A slight wrinkle to the glasses-free 3-D revolution has to do with the way in which your brain processes the sense of depth, TechPP.com noted. Displays in fixed positions offer your brain two images from a fixed point, but when these displays are ported to smartphones and other mobile screens that are in motion, the brain has a harder time processing this as truly 3-D.

If the technology ever wants to be adopted by mainstream Canadian homes, though, TechPP explained that it might not have anything to do with the TV you buy at all. Instead, it could be up to television networks and moviemakers to invest more in the technology from their side of things. Put simply, there’s no need to buy a 3-D TV if there’s no 3-D programs to watch, and the cameras required to capture video with added depth are much more expensive than most HD equipment. This leads consumers to purchase expensive displays only to be left wondering why they forked over an extra $1,000 for a feature that they never even get the chance to use.

Until the media figures out how to make filming in 3-D as easy as watching it, you might have to rely on good old physical sight to get a sense of the three-dimensional world. If you’re having any trouble with that, laser vision correction can help put things back into focus with quick and painless procedures that leave you seeing better than 20/20 in as little as 24 hours. Before you spend your next paycheck on a 3-D TV, think about investing that money in your eyesight instead.